1. Field of the Invention
The present invention relates to a small hard disk drive (HDD) assembly, a mounting structure for mounting the small HDD assembly inside an electronic device, and a mobile phone adopting the mounting structure.
2. Description of the Related Art
Hard disk drives (HDDs), which are information storage devices, reproduce data stored in a disk or record data on the disk using a read/write head. In such HDDs, the read/write head functions by being moved to a desired position by an actuator while being lifted a predetermined height above a recording surface of the rotating disk.
Recently, as portable electronic devices, such as mobile phones, personal digital assistants (PDAs), camcorders, and MP3 players, are required to have a higher performance, HDDs capable of storing a greater amount of information are employed in the portable electronic devices. Portable electronic devices are required to be lighter, thinner, and smaller, as well as have a higher performance. Accordingly, small-sized HDDs using a disk with a very small diameter, for example, a diameter of 1 or 0.85 inches, are generally employed in those portable electronic devices.
FIG. 1 is an exploded perspective view of a conventional small HDD. FIG. 2 is a perspective view of the conventional small HDD shown in FIG. 1, which is overturned.
Referring to FIGS. 1 and 2, a HDD 10 includes a base member 11 and a cover member 12 coupled to the base member 11 using a plurality of screws 19. The base member 11 supports a spindle motor 30 for rotating a disk 20 and an actuator 40 for moving a read/write head 44 to a desired position on the disk 20.
The actuator 40 includes a swing arm 42, which is rotatably coupled to an actuator pivot 41 that is installed on the base member 11, and a suspension 43, which is installed on an end portion of the swing arm 42 and elastically biases the read/write head 44 toward a surface of the disk 20. The actuator 40 includes a voice coil motor (VCM) 50 for rotating the swing arm 42. The VCM 50 includes a VCM coil 51, which is coupled to the other end portion of the swing arm 42, and a magnet 52, which is installed on the base member 11 to face the VCM coil 51. The VCM 50 is controlled by a servo control system, and rotates the swing arm 42 in a direction according to Fleming's Left Hand Rule due to an interaction between current input the VCM coil 51 and a magnetic field formed by the magnet 52.
A printed circuit board (PCB) 60 is disposed under the base member 11. The PCB 60 supports semiconductor chips 62 for operating the actuator 40, the read/write head 44, and the spindle motor 30, and various circuit elements 64.
In the meantime, as shown in FIG. 2, a motor support portion 16 for supporting the spindle motor 30 and a pivot support portion 17 for supporting the actuator pivot 41 protrude a predetermined height from a bottom surface of the base member 11. Insertion holes 66 and 67 into which the motor support portion 16 and the pivot support portion 17 are respectively inserted are formed in the PCB 60.
In the conventional small HDD 10, since the many semiconductor chips 62 and circuit elements 64 are mounted on the PCB 60, the insertion holes 66 and 67 should be as small as possible in order to secure sufficient areas for the semiconductor chips 62 and circuit elements 64. Accordingly, the motor support portion 16 for supporting the spindle motor 30 should be as small in diameter as possible, and thus, the spindle motor 30 employed in the small HDD 10 is also limited in size.
For example, for a conventional 0.85-inch diameter HDD, a spindle motor having a diameter of φ17.6 mm is generally used for that reason. Such a small spindle motor has disadvantages of a relatively low rotational stiffness Kt of 1.05 to 1.2 and a relatively high power consumption of approximately 57 mW. Additionally, in this case, it is not easy to start the motor at a low temperature.
FIG. 3 is an exploded perspective view of a portable electronic device, such as a mobile phone, on which the conventional small HDD shown in FIG. 1 is mounted. FIG. 4 is a vertical sectional view of the phone on which the conventional small HDD is mounted shown in FIG. 3.
Referring to FIG. 3, the small HDD 10 constructed as above can be mounted inside an electronic device, for example, a mobile phone 80. Specifically, the HDD 10 is mounted on a mobile phone main PCB 83 installed between a front cover 81 and a back cover 82 of the mobile phone 80. Here, damping pads 71 and 72 are interposed between the cover member 12 of the HDD 10 and the mobile phone main PCB 83 and between the PCB 60 of the HDD 10 and the back cover 82, respectively. The damping pads 71 and 72 prevent external shocks and vibrations applied to the mobile phone 80 from being transferred to the HDD 10.
Referring to FIG. 4, when the HDD 10 is mounted on the mobile phone 80, the total thickness of the mobile phone 80 is relatively high. For example, it is assumed that the 0.85-inch diameter HDD 10 is mounted on the mobile phone 80. As shown in FIG. 4, when the thickness of the 0.85-inch diameter HDD 10 including the PCB 60 is 3.3 mm and the thickness of each of the damping pads 71 and 72 is 0.5 mm, the sum of the thickness of the HDD 10 and the thicknesses of the damping pads 71 and 72 is approximately 4.3 mm. If the thickness of the back cover 82, that is, 0.8 mm, is added to the sum, the total thickness of the HDD 10, the damping pads 71 and 72, and the back cover 82 is 5.1 mm.
As described above, when small HDDs are mounted on portable electronic devices, such as mobile phones, the thickness of the portable electronic devices increases, which is not consistent with the recent trend toward lighter, thinner, and smaller portable electronic devices.
Accordingly, there are demands to minimize a thickness increment of electronic devices employing HDDs by improving mounting structures of the HDDs.